Why does DECnet Phase IV have more capabilities on VAX than on Alpha? - VMS

This is a discussion on Why does DECnet Phase IV have more capabilities on VAX than on Alpha? - VMS ; In article , Chris Scheers writes: > > If it existed on Alphas, it would be useful for accessing systems that > are not accessible from the internet. Adding an Ethernet board to an old UNIBUS, Qbus, or other VAX ...

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Thread: Why does DECnet Phase IV have more capabilities on VAX than on Alpha?

  1. Re: Why does DECnet Phase IV have more capabilities on VAX than on

    In article <5pcda4Fqboo5U1@mid.individual.net>, Chris Scheers writes:
    >
    > If it existed on Alphas, it would be useful for accessing systems that
    > are not accessible from the internet.


    Adding an Ethernet board to an old UNIBUS, Qbus, or other VAX system
    seems to make better sense than a DDCMP board on an Alpha.

    Whether any of the systems are connected to the Internet is a separate
    question.


  2. Re: Why does DECnet Phase IV have more capabilities on VAX than on Alpha?

    On Tue, 06 Nov 2007 17:56:50 -0600, Chris Scheers
    wrote:

    >no.spam@no.uce.bellatlantic.net wrote:
    >> On Tue, 06 Nov 2007 14:50:48 -0500, "Richard B. Gilbert"
    >> wrote:
    >>
    >>> AEF wrote:
    >>>> [ON TOPIC!!!]
    >>>>
    >>>> VAX can do DDCMP circuits. Alpha can't.
    >>>>
    >>> Well, I spent about 20 years in the VAX/Alpha VMS world and NEVER
    >>> encountered DDCMP! Perhaps the fact that DDCMP is almost unknown might
    >>> have something to do with it. Even if DEC supported DDCMP, did anyone
    >>> else???? It seems to me that there were a lot of LAN/WAN protocols that
    >>> never really achieved general acceptance!

    >>
    >> It was widely used between PDP-11s and VAXen in lab settings. The
    >> DDCMP is good point to point but the media was range limited even with
    >> SYNC modems which often only ran at 9600 baud. The latter is the big
    >> issue as it was rare thing to see it used with a serial line faster
    >> than 64kbaud. Even Ethernet 10mb beats that hands down but
    >> then Ethernet was far more costly than a serial line.

    >
    >I have used DDCMP on dialup modems at 19.2Kb with several clients.
    >
    >I even used it to connect from Texas to a client in London, UK. (I was
    >rather surprised at how well that worked.) At the time, overseas calls
    >were about $1/min, but it was still much less expensive than a plane ticket.
    >
    >For clients with VAXen that are not connected to the internet, it is a
    >very handy capability.
    >
    >If it existed on Alphas, it would be useful for accessing systems that
    >are not accessible from the internet.


    I used it to telecommute to the mill (DEC Maynard) via a 2400baud
    modem on my uVAX though the gandalf switch to a big VAX there.
    Even at 2400 it was mindblowing for PC users of the day for them to
    see me using PHONE, Email and doing remote account plus
    local work all with that one line.

    It was a good point to point way to connect.

    Allison



  3. Re: Why does DECnet Phase IV have more capabilities on VAX than on

    On Wed, 7 Nov 2007, Bob Koehler wrote:

    > In article <2ab7d$4730cc89$cef8887a$3152@TEKSAVVY.COM>, JF Mezei writes:
    >>
    >> (For those who don't know, DDMCP is decnet over a serial line).

    >
    > DDCMP is a line level protocol over synchronous serial lines.


    Apparently not limited synchronous serial lines.
    $ SET TERMINAL/PROTOCOL=DDCMP/SWITCH=DECNET
    is still in HELP in VMS 7.1.


    --

    Rob Brown b r o w n a t g m c l d o t c o m
    G. Michaels Consulting Ltd. (780)438-9343 (voice)
    Edmonton (780)437-3367 (FAX)
    http://gmcl.com/


  4. Re: Why does DECnet Phase IV have more capabilities on VAX than on

    On Nov 7, 1:48 pm, Rob Brown wrote:
    > On Wed, 7 Nov 2007, Bob Koehler wrote:
    > > In article <2ab7d$4730cc89$cef8887a$3...@TEKSAVVY.COM>, JF Mezei writes:

    >
    > >> (For those who don't know, DDMCP is decnet over a serial line).

    >
    > > DDCMP is a line level protocol over synchronous serial lines.

    >
    > Apparently not limited synchronous serial lines.
    > $ SET TERMINAL/PROTOCOL=DDCMP/SWITCH=DECNET
    > is still in HELP in VMS 7.1.
    >
    > --
    >
    > Rob Brown b r o w n a t g m c l d o t c o m
    > G. Michaels Consulting Ltd. (780)438-9343 (voice)
    > Edmonton (780)437-3367 (FAX)
    > http://gmcl.com/


    Yes, it can be either.

    >From the DECnet for OpenVMS manual:


    On systems that support it, DDCMP provides a low-level communications
    path between systems. The DDCMP protocol performs the basic
    communications function of moving information blocks over an
    unreliable communication channel. ... The DDCMP protocol is supported
    on some synchronous and asynchronous communications devices.

    So it can be configured for either.

    AEF


  5. Re: Why does DECnet Phase IV have more capabilities on VAX than on Alpha?

    On 6 nov, 19:33, AEF wrote:
    > [ON TOPIC!!!]
    >
    > VAX can do DDCMP circuits. Alpha can't.
    >
    > >From the DECnet for OpenVMS Networking Manual:

    >
    > "On AXP systems, Digital supports level 1 routing only for nodes
    > acting as routers for a cluster alias. Digital does not support level
    > 2 routing or routing between multiple circuits."
    >
    > It looks like routing control is also limited on Alpha.
    >
    > Also DECdns namespace appears to be missing for Alpha.
    >
    > And CI appears absent for Alpha.
    >
    > Why are all these things missing from the Alpha version? Are people
    > just expected to use Phase V and if so, does it have all these things
    > missing from Phase IV for Alpha?
    >
    > Thanks!
    >
    > AEF


    DDCMP was also supported on DECnet-RSX. An etehernet controller such
    as the DEUNA
    was an expensive device. It was very neat to run DECnet over cheap
    serial lines between PDP-11 systems
    in the factory and a VAX in the computerroom.
    Running DECnet over the CI (and over DSSI, it uses the same driver)
    allwed you to access CI cluster members
    without the necessity to buy DEUNA's (or later on DELUA's) for all VAX
    systems.
    We ran area routing on two microVAX II systems. The workstations
    (pc's, VAxmates) lived in their own area, while
    production systems (aka "real computers") were in other areas. The
    compute overhead was supposed to be killing
    for the VAXes that acted as area routers but in fact the process
    hardly showed up. Not even on the microVAX II when it
    had hundreds of pc's in its area, all connecting to a VAX 8550 in
    another area. Performance was good (10 Mb/s coaxial ethernet).
    Hans


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